1. Field of the Invention
The present invention generally relates to a magnetic recording and/or reproducing apparatus operable with a tape cassette and, more particularly, to the magnetic recording and/or reproducing apparatus of a type provided with a novel tape transport mechanism for transporting a length of magnetic recording tape from a supply reel to a take-up reel within the tape cassette by way of a head carrier.
2. Description of the Prior Art
In manufacturing the magnetic recording and/or reproducing apparatus, hereinafter referred to as a video tape player, efforts have been made to reduce the cost necessary to manufacture it in order for it to be assembled in a compact size having a light-weight feature. However, because of the nature of one or more component parts of the conventional video tape players, reduction in cost is limited.
By way of example, the conventional video tape player makes use of a complicated tape transport mechanism for driving a length of magnetic recording tape from one reel to another with the tape cassette. This tape transport mechanism used in the conventional video tape player includes a motor-coupled capstan and a pinch roller urging the length of magnetic recording tape against the capstan so that a rotary driving force exerted by the capstan can be transmitted to the length of magnetic recording tape to allow the latter to travel along a predetermined tape transport path. Also, in order for one of the reels within the tape cassette to be driven at a predetermined torque for taking up the length of magnetic recording tape driven by the capstan, the conventional video tape player makes use of a complicated clutch mechanism for controlling rotation of the reel. The details of the conventional video tape player now under discussion will be described with particular reference to FIG. 33 which schematically illustrates it as viewed from above.
Referring to FIG. 33, the standard tape cassette of a generally rectangular configuration is generally identified by 1 and includes a supply reel 2 and a take-up reel 18, both rotatably accommodated therein, and a length of magnetic recording tape 3 having its opposite ends anchored to the supply and take-up reels 2 and 18, respectively. As is well known to those skilled in the art, the tape cassette 1 has a pivotally supported side lid which is normally closed, but may be opened when the tape cassette loaded into the video tape player is set in an operative position. The tape cassette 1 also includes tape guide rollers 4a and 4b and tape guide rollers 4c, 4d and 4e rotatably positioned inside the tape cassette adjacent opposite ends of the pivotally supported side lid so that a portion of the length of magnetic recording tape 3 between the supply and take-up reels 2 and 18 may be guided so as to extend in the vicinity of and along the pivotally supported side lid.
The video tape player operable with this type of the tape cassette 1 comprises a head carrier, for example, a rotary cylinder 7 around which that portion of the magnetic recording tape 3 when drawn out from the tape cassette 1 is turned a predetermined angle so that information can be reproduced from or recorded on the magnetic recording tape 3 by means of one or more magnetic recording and/or reproducing heads carried thereby. In the illustrated video tape player, the rotary cylinder 7 makes use of four magnetic transducing heads 203a, 203b, 203c and 203d carried thereby for rotation together therewith, each neighboring members of which are spaced 90.degree. from each other about the axis of rotation of the rotary cylinder 7.
When the tape cassette 1 is loaded in the video tape player and is subsequently set in the operative position, that portion of the magnetic recording tape 3 is turned around the rotary cylinder 7 and is transported from the supply reel 2 towards the tape-up reel 18 along a predetermined tape transport path by means of a tape transport mechanism including a motor-coupled capstan 213 and a rubber-lined pinch roller 215. The tape transport mechanism is so operated that while the motor-coupled capstan 213 is driven in one direction, the rubber-lined pinch roller 215 is brought in position to urge a portion of the magnetic recording tape 3, intervening therebetween, to contact the capstan 213 so as to permit the latter to drive the magnetic recording tape 3 in one direction towards the take-up reel 18.
The prior art video tape player also comprises a full eraser head 211, disposed along the tape transport path at a location on a trailing side of the rotary cylinder 7 with respect to the direction of travel of the magnetic recording tape 3 from the supply reel 2 towards the take-up reel 18, for erasing a video signal on the length of magnetic recording tape 3 during a recording mode of the video tape player; an audio eraser head 210 and an audio control head 209 disposed along the tape transport path at a location on a leading side of the rotary cylinder 7. The audio eraser head 210 is operable to erase an audio signal on the length of magnetic recording tape 3 during the recording mode of the video tape prayer, and the audio control head 209 is operable to record an audio signal and a control signal on opposite longitudinal side edge portions of the length of magnetic recording tape 3.
The tape transport path referred to above is defined by not only the position of the rotary cylinder 7, but also a plurality of movable guide posts 204a, 204b, 203c, 204d and 204e and a plurality of movable inclined guide posts 205a and 205b as is well known to those skilled in the art. These guide posts 204a to 204d, 205a and 205b are positioned at a retracted position, shown by the phantom lines, so long as the tape cassette 1 has not yet been received in a cassette receiving chamber of the video tape player or the tape cassette 1 has not yet been set in the operative position even though the tape cassette 1 is received within the cassette receiving chamber. However, when the tape cassette 1 received within the cassette receiving chamber of the video tape player is set in the operative position, these guide posts are moved from the retracted position towards a tape path defining position shown by the solid lines by and in a manner well known to those skilled in the art in response to a signal from a cassette detector switch (not shown) with that portion of the magnetic recording tape 3 consequently turned around the rotary cylinder 7.
The capstan 213 is drivingly coupled with a drive motor 214 and is cooperable with the pinch roller 215 to drive the length of magnetic recording tape 3 in one direction along the tape transport path at a predetermined speed when the video tape player is operated in a recording mode or a reproducing mode.
Also, so long as the tape cassette 1 within the cassette receiving chamber is set in the operative position, a gear integral with a hub then coaxially connected with the supply reel 18 is engaged with a take-up drive gear 21. This take-up drive gear 21 is adapted to be driven by the drive motor 214 used to drive the capstan 213 and can, for this purpose, be drivingly connected with an endless capstan belt 218, a relay pulley 219 and an idler gear 220 selectively engageable with the take-up drive gear 21. In this design, the length of magnetic recording tape 3 then driven by the capstan 213 so as to travel towards the take-up reel 18 can be taken up around the take-up reel 18 with no substantial load imposed on a portion of the magnetic recording tape 3 on a trailing side of the capstan 213. The take-up drive gear 21 used in the prior art video tape player, however, has a torque limiter built therein, which torque limiter is in the form of a clutch mechanism such as, for example, a magnetic clutch.
As discussed above, in order for information to be recorded or reproduced on or from the length of magnetic recording tape 3, the prior art video tape player requires the use of the tape transport mechanism including the capstan and the rubber-lined pinch roller operable to bring the length of magnetic tape 3 into driving contact with the capstan. Without the tape transport mechanism, no length of magnetic recording tape 3 is transported from the supply reel towards the take-up reel at a predetermined speed synchronized with rotation of the rotary cylinder. In addition, since the pinch roller is used to urge the length of magnetic recording tape 3 into driving contact with the capstan, a substantial amount of load is necessarily imposed from the pinch roller to the capstan. Again, in order for the length of magnetic recording tape 3 to be transported at the predetermined speed synchronized with rotation of the rotary cylinder, the use of an expensive drive motor is necessitated, resulting in increase of the manufacturing cost.
Furthermore, with the torque limiter built in the reel drive gear, friction is at all times produced during the travel of the length of magnetic recording tape at the predetermined speed synchronized with rotation of the rotary cylinder and, for this reason, a loss of energies attributable to the friction is substantial.